During the proposed funding period we plan to: (a) investigate the ability of purified protein kinase catalytic subunit to phosphorylate the putative vesicular apical membranes; (b) determine whether phosphorylation alters water permeability; (c) identify, purify and incorporate phosphorylated proteins into liposomes; (d) employ the 3 proteins enriched in the apical membrane fraction as antigens to localize the cellular origin of these membranes by immunofluorescent methods; and (e) purify the basal-lateral membranes found in the 2,500 and 10,000 x g fractions in order to investigate Na ion, K ion, H ion and C1- pathways and the permutative effects of ADH in basal-lateral and apical membrane fractions.